class Puppet::Util::Lockfile

This class provides a simple API for managing a lock file whose contents are an (optional) String. In addition to querying the basic state (locked?) of the lock, managing the lock (lock, unlock), the contents can be retrieved at any time while the lock is held (lock_data). This can be used to store pids, messages, etc.

@see Puppet::Util::JsonLockfile

Attributes

file_path[R]

Public Class Methods

new(file_path) click to toggle source

   # File lib/puppet/util/lockfile.rb
13 def initialize(file_path)
14   @file_path = file_path
15 end

Public Instance Methods

lock(lock_data = nil) click to toggle source

@return [boolean] true if lock is successfully acquired, false otherwise.

   # File lib/puppet/util/lockfile.rb
26 def lock(lock_data = nil)
27   begin
28     Puppet::FileSystem.exclusive_create(@file_path, nil) do |fd|
29       fd.print(lock_data)
30     end
31     true
32   rescue Errno::EEXIST
33     false
34   end
35 end

lock_data() click to toggle source

Retrieve the (optional) lock data that was specified at the time the file

was locked.

@return [String] the data object.

   # File lib/puppet/util/lockfile.rb
54 def lock_data
55   return File.read(@file_path) if file_locked?
56 end

locked?() click to toggle source

   # File lib/puppet/util/lockfile.rb
46 def locked?
47   # delegate logic to a more explicit private method
48   file_locked?
49 end

unlock() click to toggle source

   # File lib/puppet/util/lockfile.rb
37 def unlock
38   if locked?
39     Puppet::FileSystem.unlink(@file_path)
40     true
41   else
42     false
43   end
44 end

Private Instance Methods

file_locked?() click to toggle source

Private, internal utility method for encapsulating the logic about

whether or not the file is locked.  This method can be called
by other methods in this class without as much risk of accidentally
being overridden by child classes.

@return [boolean] true if the file is locked, false if it is not.

   # File lib/puppet/util/lockfile.rb
63 def file_locked?
64   Puppet::FileSystem.exist? @file_path
65 end